Image sensing system and operating method thereof

Abstract

Disclosed is an image sensing system including an image sensor suitable for generating first actual brightness values corresponding to a captured image; and an image processor suitable for compensating for the first actual brightness values for each brightness period in a single frame period based on compensation information corresponding to a linearity error.

What is claimed is: 
     
       1. An image sensing system comprising:
 an image sensor suitable for generating first actual brightness values corresponding to a captured image; and 
 an image processor suitable for sorting the first actual brightness values for each brightness period, generating a result signal corresponding to the sorted result, and compensating for the first actual brightness values for each brightness period based on the result signal and compensation information corresponding to a linearity error, wherein the compensation information represents a slope difference for each brightness period between an actual slope and a reference slope. 
 
     
     
       2. The image sensing system of  claim 1 , wherein the slope difference is defined as a linear function for each brightness period. 
     
     
       3. The image sensing system of  claim 1 , wherein the actual slope represents a relationship between exposure times and second actual brightness values. 
     
     
       4. The image sensing system of  claim 3 , wherein the second actual brightness values are generated by the image sensor in a test mode period. 
     
     
       5. The image sensing system of  claim 3 , wherein the reference slope represents a relationship between some of the exposure times and some of the second actual brightness values. 
     
     
       6. The image sensing system of  claim 1 , wherein the image processor sorts the first actual brightness values for each color channel, and compensates for the first actual brightness values based on different pieces of compensation information. 
     
     
       7. The image sensing system of  claim 1 , wherein the image processor includes:
 a compensator suitable for compensating for the first actual brightness values for each brightness period, based on a slope difference between an actual slope representing a relationship between an exposure time and an actual brightness value, and a reference slope representing a relationship between the exposure time and a reference brightness value; and 
 a controller suitable for calculating the slope difference for each brightness period, based on second actual brightness values generated by the image sensor. 
 
     
     
       8. An image sensing system comprising:
 a compensator suitable for determining each brightness period and differently compensating for first actual brightness values generated by an image sensor, for the each brightness period, based on a slope difference between an actual slope representing a relationship between an exposure time and an actual brightness value and a reference slope representing a relationship between the exposure time and a reference brightness value; and 
 a controller suitable for calculating the slope difference for each brightness period based on second actual brightness values generated by the image sensor. 
 
     
     
       9. The image sensing system of  claim 8 , wherein the reference brightness values are some of the second actual brightness values. 
     
     
       10. The image sensing system of  claim 8 , wherein the slope difference is defined as a linear function for each brightness period. 
     
     
       11. The image sensing system of  claim 8 , wherein the controller includes:
 a first calculator suitable for calculating the actual slope based on the second actual brightness values; 
 a second calculator suitable for calculating the reference slope based on the reference brightness values; and 
 a third calculator suitable for calculating the slope difference based on the actual slope and the reference slope. 
 
     
     
       12. The image sensing system of  claim 8 , wherein the compensator includes:
 a brightness period determiner suitable for sorting the first actual brightness values for each brightness period, and generating a result signal corresponding to the sorted result; and 
 a corrector suitable for correcting the first actual brightness values based on the result signal and the slope difference. 
 
     
     
       13. The image sensing system of  claim 8 , wherein the corrector includes a multiplier and an adder. 
     
     
       14. The image sensing system of  claim 8 , further comprising a storage suitable for storing the slope difference for each brightness period. 
     
     
       15. An image sensing system comprising:
 an image sensor suitable for generating first and second actual brightness values corresponding to a captured image during first and second periods; 
 a controller suitable for determining an actual slope based on an exposure time and the second actual brightness value, determining a reference slope based on the exposure time and the actual slope, and determining a slope difference between the reference slope and the actual slope; and 
 a compensator suitable for dividing the slope difference into multiple linear functions of multiple brightness periods and compensating for the first actual brightness value for each brightness period using a corresponding linear function among the multiple linear functions. 
 
     
     
       16. An operating method of an image sensing system, comprising:
 generating one or more test images; 
 calculating an actual slope representing a relationship between exposure times and second actual brightness values and a reference slope representing a relationship between some of the exposure times and some of the second actual brightness values based on second brightness values corresponding to the test images, and generating a compensation function based on a slope difference between the actual slope and the reference slope; and 
 differently compensating for first brightness values for each output period based on the compensation function. 
 
     
     
       17. The operating method of  claim 16 , wherein the compensation function may include a linear function. 
     
     
       18. The operating method of  claim 16 , wherein the each output period may include each brightness period. 
     
     
       19. The operating method of  claim 16 , wherein the compensating of the first brightness values includes:
 dividing the slope difference into multiple linear functions of multiple brightness periods; and 
 compensating for the first brightness values for each output period using a corresponding linear function among the multiple linear functions. 
 
     
     
       20. The operating method of  claim 16 , wherein the calculating the actual slope and the reference slope includes:
 calculating the actual slope based on the second brightness values; 
 calculating the reference slope based on the some of the second brightness values; and 
 calculating the slope difference based on the actual slope and the reference slope. 
 
     
     
       21. The operating method of  claim 16 , wherein the compensating of the first brightness values includes:
 sorting the first brightness values for each brightness period; 
 generating a result signal corresponding to the sorted result; and 
 
       correcting the first brightness values based on the result signal and the slope difference.